The present invention is directed generally to means arranged within a brake drum or similar item for automatically cooling, drying and cleaning the drum in response to rotation of the drum. The invention is particularly directed to apparatus for cleaning the brake drums of heavy-duty trucks during operation of the trucks.
Approximately eighty percent of accidents involving 18-wheel tractor-trailer trucks are caused by wet brakes. To dry their brakes, truckers can power brake (drive with the left foot on the brake pedal so as to create friction and heat); however, this results in significant wear of the brake shoes and drums.
When brakes are used for lengthly time periods, powder coming off the brake lining stays between the brake shoes and the drum while the brakes are applied. Upon release of the brakes, the powder flies around the interior of the drum by centrifugal force and when the brakes are reapplied, the shoes hit the powder which then in effect becomes a grinding compound creating heat and early brake failure. The addition of rain or snow exaggerates the problem by reducing brake effectiveness even further. Consequently, the need for clean brakes has long been recognized as a major problem and has never been fully solved. Custom brake drums have been proposed including means for directing air exteriorly into the space between the wheel and brake drum but such devices are positioned radially away from the braking surfaces and their operation frequently resulted in moisture being fed into the interior of the drum along with the air intended to dry the drum. Mechanical shields have been proposed to keep the brakes dry; however, they cut off air circulation and make the brakes and wheel bearing run much hotter.
A more successful solution to these problems was proposed by this inventor and is disclosed in U.S. Pat. No. 4,621,715 which discloses an elongated flexible strip adapted to be wrapped around the peripheral wall of a brake drum adjacent the free interior edge thereof. A row of fins formed on the strip extends radially inwardly therefrom at a position adjacent to and interiorly of the interior edge of the brake drum to create suction and effect a rush of air interiorly away from the brake drum both to dissipate moisture and foreign objects on the braking surface at every r.p.m. as well as to prevent the entry of moisture from the ambient atmosphere. Whereas that invention has operated successfully, its exposed position renders it susceptible to damage. It was subsequently discovered that other structures mounted internally of the drum in a protected location could more effectively accomplish substantially the same result by blowing air interiorly across the interior surface of a brake drum rather the sucking air thereacross as in the aforementioned patent.
The last-mentioned advancements, proposed by this inventor and disclosed in applicant's pending application Ser. No. 014,834 provides a circular elongated flexible strip adapted for securement within the brake drum with a plurality of scoops or fins on the strip operating to create a rush of dry, cooling, cleansing air across the braking surface in response to rotation of the drum. Whereas the inventions of Pat. No. 4,674,606 and said pending application have likewise operated successfully in most installations, some installations involving outboard mounted drums have a relatively large air space between the elongated flexible strip and the facing surface of the drum into which the air flow from the scoops or fins is directed. The air can easily escape from such air spaces so as to reduce the velocity and pressure of the air available for cooling and/or cleaning the drum.
A basic object of the invention is the provision of new and improved air or gas blowing means.
A further object of the invention is to provide improved means for cooling, drying and cleaning the brake drums of heavy-duty trucks.
Another object of the invention is to provide such an apparatus for brake drums which is adjacent the radial wall of the drum and positioned so as not to interfere with inspection of, or access to, the brakes of a truck.
Another object of the invention is to provide such an apparatus readily suited for use with single or multiple axle vehicles and trailers.
Another object of the invention is to provide strip means having cooling, drying and cleaning fins formed thereon, which strip may be readily installed internally of both inboard mount and outboard mount conventional brake drums of various sizes without modification of the drum itself.
Yet another object of the present invention is the provision of brake cooling and cleaning means for outboard mount drums in which the airflow is maintained in relatively small conduits and chambers to minimize the reduction in pressure and velocity available for cleaning and cooling the drum.
A still further object of the invention is the provision of cooling means that can be mounted on two different drums having different numbers of mounting holes for attachment to an associated hub.
Finally, an additional object is to provide brake drum cooling and cleaning apparatus which apparatus is economical to manufacture, easy to install and efficient in operation.